Apparatus for depithing bagasse



L. FREEMAN APPARATUS FOR DEPITHING BAGASSE Aug. 8, 1967 5 Sheets-Sheet 1Filed Oct. 2'7, 1961 INVENTOR. LEO FREEMAN ATTORNEY g- 8, 1967 L.FREEMAN 3,334,386

APPARATUS FOR DEPITHING BAGASSE Filed Oct. 27, 1961 5 Sheets-Sheet :3

INVENTOR. LEO FREEMAN ATTORNEY 3%? L. FREEMAN APPARATUS FOR DEPITHINGBAGASSE 5 Sheets-Sheet 3 Filed Oct. 27, 1961 "III. VIIII'A'I INVENTOR.LEO FREEMAN ATTORNEY Aug. 8, 1967 L. FREEMAN APPARATUS FOR DEPITHINGBAGASSE 5 Sheets-Sheet 4 Filed 001;. 27, 1961 IIIIIIIIIIIIIIIIIIlI/I,1:rwuz/ l/ll INVENTOR. LEO FREEMAN ATTORNEY Aug. 8, 1967 FREEMAN APPARATUSFOR DEPITHING BAGASSE 5 Sheets-$heet 5 Filed 001;. 27, 1961 INVENTOR.

N W/ A M W E E Du F m L Y B mm W@@ 2 5 mm 3 R ATTORNEY United StatesPatent 3,334,386 APPARATUS FOR DEPITHING BAGASSE Leo Freeman, BatonRouge, La., assignor to Grundler Crusher & lulverizer Co., St. Louis,Mo., a corporation of Missouri Filed Oct. 27, 1961, Ser. No. 148,169 16Claims. (Cl. 19-34) This invention relates in general to certain new anduseful improvements in methods for depithing bagasse and to improvedapparatus therefor.

It is the primary object of the present invention to provide a novelmethod of processing bagasse whereby a very efficient and completeseparation between pith and fiber is achieved.

It is also an object of the present invention to provide a bagassedepithing process of the type stated that can be conducted in multiplestages whereby bagasse can be removed at any of the stages. 7

It is another object of the present invention to provide apparatus thatis capable of removing the pith from bagassewithout impairing the valueof the fiber.

It is also an object of the present invention to provide methods forseparating a pith-containing fibrous material such as bagasse into pithand fiber in a simple, efficient and continuous manner withoutmacerating the fibers or materially shortening them.

It is a further object of the present invention to provide a bagassedepithing apparatus of the type stated which is highly economical andefficient.

With the above and other objects in view, my invention resides in thenovel features of form, construction, arrangement, and combination ofparts presently described and pointed out in the claims.

In the accompanying drawings FIG. 1 is a front elevational view ofbagasse defiberizing apparatus constructed in accordance with andembodying the present invention;

FIG. 2 is a side elevational view of the bagasse depithing apparatusshown in FIG. 1;

FIG. 3 is a fragmentary sectional view taken along line 3-3 of FIG. 2;

FIGS. 4 and 5 are fragmentary sectional views taken along lines 44 and5--5, respectively, of FIG. 3;

FIG. 6 is a fragmentary sectional view taken along line 66 of FIG. 2;

FIGS. 7 and 8 are fragmentary sectional view taken along lines 77 and8-8, respectively, of FIG. 6;

FIG. 9 is a fragmentary perspective view of the beater arm forming apart of the present invention;

FIG. 10 is a fragmentary sectional View taken along line 10-10 of FIG.7;

FIG. 11 is a fragmentary sectional view taken along line 1111 of FIG. 2;and

FIG. 12 is a fragmentary longitudinal sectional view of a modified formof second stage pith separator constructed in accordance with andembodying the present invention.

Referring now in more detail and by reference characters to thedrawings, which illustrate practical embodiments of the presentinvention, the apparatus consists of a fed conveyor A, a bale-breaker B,a first stage or primary separator C, a second stage or secondaryseparator D a third stage or tertiary separator E, a discharge conveyorF, a primary cyclone collector G, and a secondary cyclone collector H,all connected in series substantially as shown in FIGS. 1 and 2 andpresently to be described in more detail. 1

The feed conveyor A is preferably of the conventional roller-supportedcontinuous-belt type and, therefore, need not be described orillustrated in particular detail. It is sufficient for present purposesto point out that the feed conveyor A must be of sufiicient size,strength, and speed to convey bagasse bales x to the bale-breaker B.Although, in the drawings, the bale x is shown as being tied, it isusual practice for a workman to be stationed along the feed conveyor Aand remove the bale ties just before the bale is discharged over the endof the feed conveyor A. It is also quite likely that the depithingapparatus of the present invention would be installed in, or adjacentto, a sugar plant so that the bagasse would be deposited upon the feedconveyor in unbaled or loosely consolidated form. It should, therefore,be understood that the present invention is in no way limited to theform or condition in which the bagasse is deposited upon the feedconveyor A.

The first stage or primary pith separator C comprises a semi-cylindricaltop member 1 provided along its longitudinal margins with horizontalflanges 2, 3, secured by means of bolts 4, 5, to matching flanges 6, 7,formed along the longitudinal margins of a semi-cylindrical screen 8preferably having the same radius as the top member 1. Suitably mountedacross the ends of the top member 1 and screen 8 are end walls 9, 10,thereby forming a horizontal cylindrical beater-chamber 11. Bolted toand extending through one end of the top member 1 is a tubular intakechute 12 by which the bagasse is transferred from the bale-breaker B tothe interior of the pith separator C. Similarly mounted in the other endof the pith separator C is a tubular discharge pipe 13 by which fiber isdelivered to the intake end of the secondary separator D.

Rigidly bolted to the underside of the screen 8 is a discharge pan 14provided with two vertical side walls 15, 16, integrally provided ontheir lower margins with two inwardly and downwardly converging bottomwalls 17, 18, which, in turn, merge into a downwardly project ingdischarge pipe 19, the latter being connected by an air-pipe 20 to acentrifugal blower 21, the discharge side of which is likewise connectedby an air-pipe to the intake of a cyclone separator 22. In order toprovide free entry of air into the interior of the beater-chamber 11,the top member 1 is provided with a plurality of apertures 23, as bestseen in FIG. 3.

The end walls 9, 10, are respectively provided with concentric apertures24, 25, for accommodating an axially extending agitator shaft 26 mountedin bearings 27, 28, operatively supported in bearing housings 29, 30,bolted or otherwise rigidly secured to horizontally extending brackets31, 32, which are, in turn, rigidly secured upon the outer faces of theend walls 9, 10, respectively. The rotatable agitator shaft 26 is drivenby a conventional electric motor 33 which is also mounted on the bracket31. Mounted on the shaft 26 by means of set screws 34 is a series ofagitator elements 35, each having a central hub 36 and diametrallyopposite paddle-like blades 37 which are provided with a pitch that willpropel the bagasse axially through the beater-chamber 11 and subject itto a substantial degree of disintegration before reaching the dischargepipe 13. Also mounted on the shaft 26 and secured thereto by a set screw38 is a fiber discharging element 39 having a hub 40 and relativelylarge non-inflected blades 41, 42 to propel the fiber into the dischargepipe 13.

The blower 21, the cyclone separator 22, and the motor 33, areconventional and, therefore, are not illustrated nor described in detailherein.

The discharge pipe 13 is preferably rectangular in cross-sectional shapeand opens laterally into the upper end of the second stage pithseparator D. Communicating with the rectangular discharge pipe 13 at thepoint of entry into the separator D is a second rectangular dischargepipe 43 for optionally delivering fiber from the first stage separator Cto a conveyor 44. A valve plate 45 is pivotally mounted in thepassageway of the discharge pipe 13 at the region of connection to thedischarge pipe 43 by means of a shaft 46 which is provided with an externally accessible handle 47 for providing optional delivery betweeneither of the two discharge pipes 13, 43.

The second stage pith separator or so-called scrubber D comprises asemi-cylindrical top member 48 provided along its longitudinal marginwith outwardly extending flanges 49, 50, which are tightly secured bymeans of a series of bolts 51 to matching flanges 52, 53, formedintegrally along the upper longitudinal edges of a bottom member 54having spaced parallel side walls 55, 56, and downwardly convergingangular bottom walls 57, 58. Along their transverse margins, the topmember 48 and the bottom member 54 are respectively provided with endflanges 59, 60, 61, 62. Bolted to and extending transversely across theend flanges 59, 61, is a flat lower end wall 63 and similarly bolted toand extending transversely across the end flanges 60, 62, is an upperend wall 64, thereby forming an enclosed chamber 65. As may be seen byreference to FIG. 6, the second stage pith separator D is mounted insome conventional manner by suitable structural members (not shown) soas to be disposed with its longitudinal axis at a moderate downwardlyinclined angle from its upper end wall 64 to its lower end wall 63. Thechamber 65 is provided, upon its interior surface, with two axiallyspaced sets of trunnion supported rollers 66a, 66b, 660, 67a, 67b, 67c,respectively supporting mounting rings 68, 69, which, in turn, aresecured externally to and operatively support a rotating screen 70 whichconsists of an elongated screen element 71 which is preferably hexagonalin cross-section and tapers slightly from its upper end to its lowerend, such lower end being rigidly mounted in a cylindrical screenelement 72 which is substantially larger in diametral size than theuppermost portion of the hexagonal screen element 71. At its upper end,the hexagonal screen element 71 is provided with an inwardly turnedannular flange 73 which defines a relatively large opening 74 forreceiving the stream of fiber which is discharged thereinto from theoblique spout portion 75 which extends through the end upper wall 64from the lower end of the discharge pipe 13. Similarly, the lower end ofthe cylindrical screen element 72 is provided with an inwardly turnedannular flange 76 which defines a relatively large opening 77communicating to the open upper end of a discharge spout 78 which isconnected to the upper end of, and forms a part of, a downwardlyextending discharge pipe 79.

Rigidly mounted upon, and encircling, the hexagonal screen element 71approximately midway between the upper end wall 64 and the lower endwall 63 is a ringtype worm gear 80 which meshes with a driving worm 81pinned upon a shaft 82 which is, in turn, journaled in bearings 83, 84,the latter being mounted in, and extending through, the top member 48.At one end, the shaft 82 projects outwardly and is operatively connectedto a conventional electric motor 85 mounted upon a horizontal bracket 86which is welded or otherwise rigidly secured upon the external face ofthe top member 48, all as best seen in FIG. 8.

The end walls 63, 64, are provided with concentric apertures 87, 88, foraccommodating an elongated beatershaft 89 which extends axially throughthe second stage pith separator D and is operatively journaled inbearings 90, 91, which are, in turn, mounted in bearing-supports 92, 93,the latter being respectively supported on brackets 94, 95, which arewelded or otherwise rigidly secured to the outer faces of the end walls63, 64. The lower end of the shaft 89 is operatively connected to anelectric motor 96 which is also rigidly secured upon the bracket 94. Atuniformly spaced intervals along its length between the end walls 63,64, the shaft 89 is provided with a series of beater-arms 97, each beingintegrally provided at its inner end with a hub 98 which is secured tothe shaft 89 by means of a set screw 99. The beater-arms 97 arerelatively flat and blade-like in shape, being angularly deflected so asto propel the fibers from the upper end to the lower end of the rotatingscreen 70. Each of the beater-arms 97 is, furthermore, provided at itsouter end with a short piece of free-swinging chain 100 which is of suchlength as to almost, but not quite, touch the surfaces of the screenelements 71, 72, as best seen in FIGS. 7 and 8. Moreover, the directionof rotation of the electric motors 85, 96, is such that the screen 78will rotate in one direction and the shaft 89 will rotate in theopposite direction. In other words, the shaft 89 and beaterarms 97 arecounter-rotating with respect to the screen 70.

The downwardly converging walls 57, 58, of the bottom member 54 actuallyfunnel into a downwardly projecting discharge spout 101 which isconnected to the upper end of a discharge pipe 102, which is, in turn,connected to the intake side of a conventional centrifugal blower 103.The discharge side of the centrifugal blower 103 is connected by anair-pipe 104 to a second conventional cyclone separator 105.

As will be seen by reference to FIGS. 7 and 8, the end walls 63, 64, areprovided with a plurality of air inlet apertures 106, each of which iscovered over with a piece of screen wire or similar foraminous material107 held in place by an annular frame 108, the latter being rigidlysecured by screws 109. The screen covered apertures 106 are relativelylarge so that air may be freely drawn therethrough and through thechamber 65 by means of the blower 103. It will also be noted, byreference to FIG. 6, that the beater-arms 97 which are located withinthe hexagonal screen element 71 are oriented at 90 to each other aroundthe shaft 89 and the two beater-arms 97 which are located in thecylindrical screen element 72 are in diametral orientation with respectto each other. The discharge pipe 79, at its lowerend, opens into aninverted Y so as to provide a lateral discharge spout 110 extendingangularly in one direction and a lateral tubular chute 111 extendingangularly in the opposite direction. The discharge spout 110 opens.downwardly into a short vertical discharge leg 112 which dischargesdownwardly onto a fiber conveyor 113. The tubular chute 111, in turn,opens downwardly into the third stage or tertiary separator E, which isof substantially the same type as that described in United States PatentNo. 2,825,935, issued Mar. 11, 1958. Inasmuch as the tertiary separatorE is fully described in said patent, it is sufficient, for presentpurposes, to note that the tertiary separator E includes a pithdischarge chute 114 which discharges downwardly onto a conveyor 115 anda fiber discharge chute 116 which discharges downwardly onto a conveyor117. In the region of the separator between the discharge spout 110 andthe discharge chute 111 is a horizontal shaft 118 which operativelysupports a deflector plate 119 and is externally provided with a handle120. By shifting the deflector plate from the position shown in fulllines to the position shown in dotted lines in FIG. 11, it is possibleto direct the flow of fiber to the conveyor 113 or to the tertiaryseparator E.

It will also be noted by reference to FIGS. 1 and 2 that the cycloneseparators 22 and 105, respectively, have airdischarge ducts 121, 122,and pith discharge spouts 123, 124.

The bagasse enters the first stage or primary separator C through thetubular intake chute 12 and is subjected to the beating action of thepaddle-like'blades 37 which break up the bagasse and loosen a largepercentage of the fibers and pith. The pith is drawn downwardly throughthe screen 8 and delivered into the cyclone separator 22. The fiber,which still contains a certain percentage of pith, drops over the end ofthe screen 8 into the discharge pipe 13 and is delivered into therotating hexagonal screen element 71 of the secondary separator orso-called scrubber D, in which it is again subjected to beating actionas it progresses down the inclined hexagonal screen element 71 and intothe screen element 72. The air which is being drawn through thesecondary separator D by means of the blower 103 will draw the piththrough the upon the conveyor 113 or may be subjected to a further andfinal polishing operation in the tertiary separator E. The pith from thesecondary separator or scrubber D is conveyed by means of the blower 103to the cyclone separator 105. If the fiber is given a final polishingoperation in the tertiary separator E, the very small amount of pithdeveloped will be deposited on the conveyor 115 and the substantiallypure pith-fiber will be deposited on the conveyor 117 for transportationto some suitable point of ultimate use.

It is possible to provide a modified form of the second stage pithseparator D, as shown in FIG. 12, which is similar in most respects tothe previously described second stage pith separator D, except thatmeans are provided for Washing the pith and fiber during the separatingaction. The secondary unit D, similarly consists of an open-endedhexagonal revolving screen 125 that is supported at its right transversemargins by spool-shaped rollers 126, which are similar in all respectsto the previously described rollers 66a, 66b, 66c, and 67a, 67b, 670. Ahollow agitator shaft 89 is rotatably mounted in bearings 127 which are,in turn, mounted in a bearing housing 128, the shaft 89 being providedwith a central axial bore 129. Welded to the shaft 89' are axiallyspaced radially extending agitator blades 130 having axially extendingcentral bores 131 which communicate with the central bore 129 of theagitator shaft 89'. Each agitator blade 130 is also provided with aU-shaped bight portion 132 at its outer end having transversely alignedapertures 133 for accommodating a bolt 134 for rigidly attaching alength of chain 135 to the blades 130. The blades 130 are, moreover,provided with a series of radially extending tubular channels 136 whichcommunicate with the axially extending central bores 131. One end of thehollow agitator shaft 89 is mounted in a stufling box 137, which is, inturn, mounted on a horizontal bracket 138 and is provided with a centralbore 139 sized to accommodate the shaft 89'. Moreover, the stufiing box137 is provided with an annular sealing ring 140 for maintaining afluid-tight seal around the outer peripheral surface of the shaft 89'and is finally provided with an axially extending tubular channel 141 incommunication with the bore 139. A fluid coupling 142 is threadedlyattached to the outer end of the channel 141 for connection to anysuitable source of rinse water.

The second stage pith separator D' operates in a manner similar to themanner previously described pith separating unit D. The hexagonal screen125 rotates in one direction as the agitator shaft 89 rotates in anopposite direction. Water is admitted to the rotating hollow shaft 89'through the stufiing box 137. As the tubular channels 136 communicatewith the axial central bore 131 of the agitator blade 130 which, inturn, communicates with the bore 129, water under pressure will beforced out of the tubular channels 136 providing a scrubbing and washingaction for separating the pith and fiber. Moreover, this washing andrinsing action will tend to cleanse the chain links 135 and screen 125.

It should be understood that changes and modifications in the form,construction, arrangement, and combination of the several parts of thedepithing processes may be made and substituted for those herein shownand described without departing from the nature and principle of myinvention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. An apparatus for removing pith from fibrous plant stalks such asbagasse and the like; said apparatus comprising a first separator unitfor separating the plant stalks into pith and fiber, the first separatorunit having an inlet for receiving the plant stalks, an outlet forexpellin-g the separated fibers, and a pith collecting member forreceiving the separated pith; a second separator unit including ahousing, a screen rotatably mounted within the housing, the housinghaving an inlet which opens into one end of the screen, an outlet whichcommunicates with the opposite end of the screen, and a pith collectingmember disposed beneath the screen, a beater shaft rotatably mounted onthe housing and extending coaxially through the screen, a plurality ofblades mounted on the beater shaft and being pitched for propelling thefibers along the interior of the screen from the inlet to the outlet,and power means for rotating the beater shaft and the screen; and afirst discharge chute interconnecting the outlet of the first separatorunit with the inlet of the housing forming part of the second separatorunit, whereby the fiber discharged from the first separator unit isconveyed to the second separator unit for further depithing.

2. An apparatus according to claim 1 in which the beater shaft andscreen rotate in opposite directions.

3. An apparatus according to claim 2 and further characterized by pithcollecting means, a first discharge pipe interconnecting the pithcollecting means and the pith collecting member of the first separatorunit; and a second discharge pipe interconnecting the pith collectingmeans and the pith collecting member of the second separator unit. 7

4. An apparatus according to claim 3 in which the pith collecting meansincludes first and second cyclone collectors connected to the first andsecond discharge pipes, respectively, said apparatus being furthercharacterized by first and second blowers interposed in the first andsecond discharge pipes so as to establish an air stream therein forconveying the pith to the cyclone collectors.

5. An apparatus according to claim 2 in which the screen includes afirst screen element and a second screen element, which is greater intransverse Width than the first screen element, the second screenelement being located adjacent the outlet in the housing.

6. An apparatus according to claim 5 in which the first screen elementtapers slightly toward the second screen element.

7. An apparatus according to claim 5 in which the first and secondscreen elements are of polygonal and cylindrical cross-sectional shape,respectively.

8. An apparatus according to claim 7 in which the common axis of thescreen and beater shaft is tilted slightly downwardly toward the outletof the housing.

9. An apparatus according to claim 7 and further characterized bychain-like elements mounted on the ends of the blades forcircumferential movement in close proximity to the inner surfaces of thescreen elements.

10. An apparatus according to claim 1 in which the common axis of thescreen and beater shaft is tilted downwardly toward the outlet of thesecond separator unit.

11. An apparatus according to claim 1 in which the screen has apolygonal cross-sectional shape.

12. An apparatus according to claim 1 in which the screen has ahexagonal cross-sectional shape.

13. An apparatus according to claim 1 and further characterized bychain-link elements mounted at the ends of the blades forcircumferential movement in close proximity to the inner surface of thescreen.

14. An apparatus according to claim 1 in which the screen tapersslightly from the inlet to the outlet of the second separator unit.

15. An apparatus according to claim 1 and further characterized 'by avalve interposed in the first discharge chute for optionally directingthe fiber to the second separator unit or out of the first dischargechute prior to the second separator unit. I

16. An apparatus according to claim 15 and' further characterized by athird separator unit for further depithing the fibers discharged fromthe outlet of the second separator unit, a second discharge chuteinterconnecting the outlet of the second unit and the third unit, and avalve interposed in the second discharge chute for optionally directingthe fiber to the third separating unit or withdrawing it from theapparatus.

References Cited UNITED STATES PATENTS 460,274 9/ 189 1 Wendel 209-295 8Rowland et a1 209 -292 ORourke 19-34 Vissac 209316 X Horton et al 19-7 XFreeman 198 Horton et a1 1990 Sheldon 19-90 Freeman 19-90 Nolan 19-8FOREIGN PATENTS Great Britain.

ROBERT R. MACKEY, Primary Examiner.

5/1902 Krapf 209-495 15 DONALD PARKER, Examiner.

1. AN APPARATUS FOR REMOVING PITH FROM FIBROUS PLANT STALKS SUCH ASBAGASSE AND THE LIKE; SAID APPARATUS COMPRISING A FIRST SEPARATOR UNITFOR SEPARATING THE PLANT STALKS INTO PITH AND FIBER, THE FIRSTSEPAARATOR UNIT HAVING AN INLET FOR RECEIVING THE PLANT STALKS, ANOUTLET FOR EXPELLING THE SEPARATED FIBERS, AND A PITH COLLECTING MEMBERFOR RECEIVING THE SEPARATED PITH; A SECOND SEPARATOR UNIT INCLUDING AHOUSING, A SCREEN ROTATABLY MOUNTED WITHIN THE HOUSING, THE HOUSINGHAVING AN INLET WHICH OPENS INTO ONE END OF THE SCREEN, AN OUTLET WHICHCOMMUNICATES WITH THE OPPOSITE END OF THE SCREEN, AND A PITH COLLECTINGMEMBER DISPOSED BENEATH THE SCREEN, A BEATER SHAFT ROTATABLY MOUNTED ONTHE HOUSING AND EXTENDING COAXIALLY THROUGH THE SCREEN, A PLURALITY OFBLADES MOUNTED ON THE BEATER SHAFT AND BEING PITCHED FOR PROPELLING THEFIBERS ALONG THE INTERIOR OF THE SCREEN FROM THE INLET TO THE OUTLET,AND POWER MEANS FOR ROTATING THE BEATER SHAFT AND THE SCREEN; AND AFIRST DISCHARGE CHUTE INTERCONNECTING THE OUTLET OF THE FIRST SEPARATORUNIT WITH THE INLET OF THE HOUSING FORMING PART OF THE SECOND SEPARATORUNIT, WHEREBY THE FIBER DISCHARGEED FROM THE FIRST SEPARATOR UNIT ISCONVEYED TO THE SECOND SEPARATOR UNIT FOR FURTHER DEPITCHING.